1. Field of the Invention
The present invention generally relates to a metal trench de-coupling capacitor structure. In particular, the present invention is directed to a deep metal trench de-coupling capacitor structure, to avoid the interference of power noise.
2. Description of the Prior Art
Generally speaking, as shown in FIG. 10, semiconductor elements 40 are usually various semiconductor elements 40 disposed on the element region 41 of the substrate 10. Optionally, the element region 41 may include various electronic elements. For example, various adjacent element regions 41 include electronic elements generating different types of signals. For instance, various adjacent element regions 41 may be a digital circuit element region 42, a radio frequency (RF) circuit element region 43, or an analog circuit element region 44. Because element regions 41 of different functions generate different types of signals, these signals may couple one another by means of common power, or become the noise of other signals.
Generally speaking, element regions 41 of different functions tolerate noise differently. For example, a digital circuit element region 42 generates digital signals. On one hand, the quality of a digital signal is indifferent to a considerable amount of noise which the digital signal itself carries. On the other hand, either a pure digital signal itself or its associated noise is likely to become the noise of other kinds of more sensitive signal types. Relatively speaking, a digital circuit element region 42 carries more noise than other element regions. In other words, the digital signal itself is indifferent to noise, but it could be the source of noise to other types of signals which are more sensitive to noise. In short, different element regions may tolerate power noise differently.
Because the power domains are increasing and the operational frequencies are increasing as well, they make power noise stronger and stronger because the sudden change of the electric current generates voltage pulse caused by the inductive behaviors of metal wires. Therefore, a new way is still needed to minimize as much as possible or to even eliminate the influence of power noise on different element regions. Preferably, it is also compatible with the current semiconductor manufacturing process.